CJ2 CPU Unit Software User's Manual - CIP ETI

5 Understanding Programming5-1-3 ST LanguageThe ST (Structured Text) language is a high-level language code for industrial controls (mainly PLCs)defined by the IEC 61131-3 standard. The standard control statements, operators, and functions makethe ST language ideal for mathematical processing that is difficult to write in ladder programming. (TheST language does not support all of the processing that can be written in ladder diagrams. The ST languagethat conforms to the IEC 61131-3 standard is supported.Additional InformationFor details on ST programming specifications, notation, and input procedures, refer to the CX-Programmer Operation Manual: Function Blocks and Structured Text (Cat. No. W447). Features of ST Programming• There are many control statements available, such as loop statements and IF-THEN-ELSE statements,many operators such as arithmetic operators, comparison operators, and AND/OR operators,as well as many mathematical functions, string extract and merge functions, Memory Cardprocessing functions, string transfer functions, and trigonometric functions.• Programs can be written like high-level languages such as C, and comments can be included tomake the program easy to read.• ST programs can be uploaded and downloaded just like ordinary programs, but ST program taskscannot be uploaded and downloaded in task units.• Function blocks (ladder or ST language) can be called in ST programs.• One-dimensional array variables are supported for easier data handling in applications. SpecificationsItemST program unitsAddress specifying procedureForce-setting and force-resettingOnline editingSpecification• Tasks• Algorithms for function block definitions• Action programs and transition programs in SFCs.Addresses are specified using symbols. Any address can be assigned to thesymbol.Supported.ST program editing5-8 CJ2 CPU Unit Software User’s Manual